This invention relates to mandrels for use on automatic packaging machines and more particularly to mandrels for picking up and carrying products having any of a plurality of different widths.
As used herein a mandrel is a device carried by a link chain conveyor of an automatic packaging machine. Usually, it has been necessary to readjust an automatic packaging machine when one type of mandrel is replaced by another type of mandrel.
These mandrels may perform any of many different functions such as carrying boxes, bottles, packets or performing other suitable functions. Usually, each mandrel is especially adapted to perform a specific function. For example, a conventional mandrel which might carry and shape a bag of peas to fit into a frozen food carton, but that same mandrel cannot carry a bottle to receive pills. Heretofore, a mandrel which can carry a box cannot set it down temporarily to weigh its contents, for example, and then pick it up again to complete its trip through the packaging machine.
Heretofore, it has been common practice to design an automatic packaging machine from start to finish, which has been a relatively expensive procedure. The present inventor has designed such packaging machines with a modular construction in order to produce a new automatic packaging machine by selecting and assembling preexisting modules. Therefore, there are existing mandrels and platforms for mandrels which may be selected and used in different configurations. Hence, if a new mandrel is required, there is a savings if that new mandrel can be carried on and supported on an existing platform.
Accordingly, an object of the invention is to provide mandrels which may carry boxes or other objects of almost any shape or size, within reason. Here an object is to provide such mandrels which can be oriented either horizontally or vertically and which can be changed without having to readjust the basic automatic packaging machine. A further object is to provide mandrels of design which may be easily enlarged or reduced in size, or otherwise modified, with little or no significant amount of original engineering required in order to accommodate different types of end products.
Another object of the invention is to provide new and novel mandrels which can be carried on and operated by existing platforms. Still another object is to provide mandrels which carry a product in a self-holding or locking manner so that no positive and continuous holding force need be applied by the automatic packaging machine. Here, an object is to provide mandrels which are self-holding responsive to a spring force and which are opened responsive to an instantaneous location of said mandrel along the conveyor path.
In keeping with an aspect of this invention, an automatic packaging machine has a conveyor accompanied by a cam track with contours which define work stations and other locations along the conveyor. A variable width mandrel is adapted to carry objects having any of a plurality of different widths. A coiled spring closes the mandrel to grip an object as it travels with the conveyor. The cam track expands the mandrel to release a grip on the conveyed objects. This way, a change in the width of the object being carried does not require a readjustment of the machine. In addition, the machine may drop and retrieve the objects as a function of the cam track contour. For example, the object may be briefly set on a scale to weigh, its content and then picked up and carried on.